Kaksivärisyys

Kaksivärisyys, also known as dichromatism, is a form of color vision deficiency where an individual has only two types of cone cells in their eyes instead of the usual three. This means they can perceive only two primary colors, typically red and blue, or green and blue, and their perception of the color spectrum is limited. The most common forms of kaksivärisyys are protanopia and deuteranopia, which affect red and green perception, respectively, and tritanopia, which affects blue and yellow perception.

Individuals with kaksivärisyys may have difficulty distinguishing between certain colors. For example, protanopes and deuteranopes often confuse reds, greens, oranges, and browns. Tritanopes have trouble with blues and yellows, and may also see purples as dark blues. The severity of kaksivärisyys can vary, with some individuals having only mild difficulties and others experiencing more significant color vision impairment.

Kaksivärisyys is usually inherited and is more common in males than females. It is caused by a genetic mutation on the X chromosome that affects the development of the cone cells responsible for detecting specific wavelengths of light. While there is no cure for kaksivärisyys, individuals can learn to adapt and use other cues, such as brightness or context, to help distinguish colors. Specialized lenses and apps can also assist in identifying colors.